Only calculate slave->build mapping once in json output.

third_party/buildbot_8_4p1/buildbot/status/web/status_json.py

Index: third_party/buildbot_8_4p1/buildbot/status/web/status_json.py
diff --git a/third_party/buildbot_8_4p1/buildbot/status/web/status_json.py b/third_party/buildbot_8_4p1/buildbot/status/web/status_json.py
index b656563257e3b0dbe89ca0e3fe26b330c1e7d99b..9ece8200b2460f06c69abff339a8497753e4e05e 100644
--- a/third_party/buildbot_8_4p1/buildbot/status/web/status_json.py
+++ b/third_party/buildbot_8_4p1/buildbot/status/web/status_json.py
@@ -16,6 +16,7 @@
 
 """Simple JSON exporter."""
 
+import collections
 import datetime
 import os
 import re
@@ -414,12 +415,14 @@ class BuilderSlavesJsonResources(JsonResource):
     pageTitle = 'BuilderSlaves'
 
     def __init__(self, status, builder_status):
+        buildcache = collections.defaultdict(dict)
         JsonResource.__init__(self, status)
         self.builder_status = builder_status
         for slave_name in self.builder_status.slavenames:
             self.putChild(slave_name,
                           SlaveJsonResource(status,
-                                            self.status.getSlave(slave_name)))
+                                            self.status.getSlave(slave_name),
+                                            buildcache=buildcache))
 
 
 class BuildJsonResource(JsonResource):
@@ -620,12 +623,17 @@ class SlaveJsonResource(JsonResource):
 """
     pageTitle = 'Slave'
 
-    def __init__(self, status, slave_status):
+    def __init__(self, status, slave_status, buildcache):
         JsonResource.__init__(self, status)
         self.slave_status = slave_status
         self.name = self.slave_status.getName()
         self.builders = None
 
+        # buildcache is used to cache build information across multiple
+        # invocations of SlaveJsonResource. It should be set to an empty
+        # collections.defaultdict(dict).
+        self.buildcache = buildcache
+
     def getBuilders(self):
         if self.builders is None:
             # Figure out all the builders to which it's attached
@@ -635,21 +643,24 @@ class SlaveJsonResource(JsonResource):
                     self.builders.append(builderName)
         return self.builders
 
+    def getSlaveBuildMap(self):
+        if not self.buildcache:
+            for builderName in self.getBuilders():

[iannucci, 2013/06/28 23:25:53]

So the code inside the if statement will be executed exactly once per web
request?

+                builder_status = self.status.getBuilder(builderName)
+                for i in range(1, builder_status.buildCacheSize - 1):
+                    build_status = builder_status.getBuild(-i)
+                    if not build_status or not build_status.isFinished():
+                        # If not finished, it will appear in runningBuilds.
+                        break
+                    slave = self.buildcache[build_status.getSlavename()]
+                    slave.setdefault(builderName, []).append(
+                            build_status.getNumber())
+        return self.buildcache[self.name]
+
     def asDict(self, request):
         results = self.slave_status.asDict()
         # Enhance it by adding more informations.
-        results['builders'] = {}
-        for builderName in self.getBuilders():
-            builds = []
-            builder_status = self.status.getBuilder(builderName)
-            for i in range(1, builder_status.buildCacheSize - 1):
-                build_status = builder_status.getBuild(-i)
-                if not build_status or not build_status.isFinished():
-                    # If not finished, it will appear in runningBuilds.
-                    break
-                if build_status.getSlavename() == self.name:
-                    builds.append(build_status.getNumber())
-            results['builders'][builderName] = builds
+        results['builders'] = self.getSlaveBuildMap()
         return results
 
 
@@ -659,11 +670,13 @@ class SlavesJsonResource(JsonResource):
     pageTitle = 'Slaves'
 
     def __init__(self, status):
+        buildcache = collections.defaultdict(dict)
         JsonResource.__init__(self, status)
         for slave_name in status.getSlaveNames():
             self.putChild(slave_name,
                           SlaveJsonResource(status,
-                                            status.getSlave(slave_name)))
+                                            status.getSlave(slave_name),
+                                            buildcache=buildcache))
 
 
 class SourceStampJsonResource(JsonResource):